Wells – Above ground apparatus – With assembly or disassembly means
Reexamination Certificate
2000-05-04
2001-08-21
Suchfield, George (Department: 3672)
Wells
Above ground apparatus
With assembly or disassembly means
C166S077100, C166S091100, C166S097100
Reexamination Certificate
active
06276451
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a pressure relief system for use in live well snubbing.
2. Description of the Related Art
For the insertion of piping and tools into live well bores, and the extraction of piping and tools from live well bores, known as “snubbing”, it is conventional to employ a snubbing unit provided with one or more blow-out preventers (BOPs), which are closed into pressuretight engagement with the piping in order to prevent leakage of gas under pressure from the well bore.
During conventional snubbing operations, it is considered standard procedure to operate at the available surface pressure. For example, for a well having 4,500 psi surface pressure, then this pressure would typically be consistently maintained at the uppermost blow-out preventer while performing snubbing or stripping operations through annular BOPs.
The present invention is based on the concept that it would be desirable to reduce the pressure between the well bore and the apparatus employed for snubbing, thereby reducing unnecessary risks and improving the safety of what would otherwise normally be considered to be a very hazardous operation, i.e. moving pipe through blow-out preventers at a pressure differential of 4,500 psi
BRIEF SUMMARY OF THE INVENTION
According to the present invention, there is provided a pressure relief system for use in live well snubbing, between the well bore and an overlying snubbing installation, which comprises a plurality of blow-out preventers mounted one above the other on the well bore, with a plurality of spools installed between successive ones of the blow-out preventers, the spools and the blow-out preventers being arranged along a passage communicating with the well bore and serving to receive piping therethrough during snubbing operations. Gas supply ducts communicate with the passage between successive ones of the blow-out preventers and are provided with gas pressure regulators, so that the pressure in the passage progressively increases along the passage in an upward direction.
In a preferred embodiment of the invention, pressure bleed-off ducts communicate with the passage between the blow-out preventers and are provided with pressure relief valves for limiting the pressures in the passage between successive ones of the blow-out preventers.
REFERENCES:
patent: 1836508 (1931-12-01), Rasmussen
patent: 3207221 (1965-09-01), Cochran et al.
patent: 3338302 (1967-08-01), Hubby
patent: 3457991 (1969-07-01), Sizer et al.
patent: 3589667 (1971-06-01), Lewis et al.
patent: 3637009 (1972-01-01), James
patent: 3804175 (1974-04-01), Miller
patent: 4046191 (1977-09-01), Neath
patent: 4440232 (1984-04-01), LeMoine
LandOfFree
Pressure relief system for live well snubbing does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Pressure relief system for live well snubbing, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pressure relief system for live well snubbing will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2528933